1. Field of the Invention
The present invention relates to an optimized path establishment method and a network management system using the optimized path establishment method. More particularly, the present invention relates to a method for establishing an optimized path by selecting an optimum route which connects subnetworks and to a network management system using the optimized path establishment method, wherein the subnetwork is a smallest management unit in network element groups which form a transmission network.
2. Description of the Related Art
Conventionally, routing technologies for avoiding various failures on paths under operation are disclosed in a transmission network management field. According to the routing technologies, a network manager determines an optimum route on the basis of minimum distance, traffic, available capacity, number of failures and the like manually, and the network manager generates a routing table from the optimum route beforehand. In addition, every time when a network configuration is changed, the network manager updates the routing table to a newest one.
There are following problems when the network management system has the routing table which is fixedly generated by the network manager beforehand.
First, since the number of network elements which form the subnetwork is very large in a large transmission network, it takes much time to check manually every route which connects endpoints when designing such a large transmission network. Second, in order to implement a network configuration according to network design, it is necessary to incorporate the routing table which is designed beforehand into the network management system.
Third, when a subnetwork is added or removed in the large transmission network, it is necessary to redesign a plurality of routes in consideration of all surrounding subnetworks which are physically connected to the added or removed subnetwork. Therefore, the routing table, which includes fixed data, needs maintenance frequently.
Fourth, as preparedness of a failure in a transmission network which is under operation, it is necessary to reserve alternative routes. Therefore, there are redundant network resources.
Fifth, since network design is performed by the network manager manually, there is a high possibility that the optimum route is overlooked due to a mistake or lack of consideration in designing.
Sixth, when establishing a path, it is necessary to specify subnetworks and CTPs in each subnetwork one by one, in which the CTP is a connection point between a subnetwork and an adjacent subnetwork located in the edge of the subnetwork.
Seventh, since the path establishment operation abends when path establishment fails in midstream, an operation to continue the path establishment becomes necessary.
Eighth, the network manager may be forced to correct the routing table when path establishment fails. Thus, it takes much time to complete the path establishment operation.